To join workpieces using linear friction welding, the workpieces must be urged toward one another, while at least one of the workpieces is oscillated relative to the other workpiece. To appropriately position the workpieces with respect to one another and to provide the biasing force and the oscillating motion required to weld the workpieces together, linear-friction-welding machines have been developed.
Conventional single-axis linear-friction-welding machines generally include a stationary table for supporting a first workpiece and a weld head for biasing a second workpiece against the first workpiece and for providing a linear oscillation of the second workpiece relative to the first workpiece to friction weld the workpieces together. To permit the workpieces to be controllably positioned with respect to one another for welding, single-axis linear-friction-welding machines use part/weld-unique tooling.
Conventional three-axis linear friction welding machines generally include a table configured to be movable along a plane defined by two orthogonal axes, such as the X axis and the Y axis. For purposes of providing a biasing force between the two workpieces during the welding operation, the weld head may be configured to be movable along a third axis, orthogonal to the first two axes, e.g., the Z axis. The movable table may be translated along the X-Y plane to generally align the first workpiece, supported by the movable table, with the second workpiece, coupled to the weld head, along the Z axis. The weld head may then be positioned along the Z-axis to bias the second workpiece against the first workpiece with a predetermined force, while linearly oscillating the second workpiece relative to the first workpiece at a predetermined frequency, thereby friction welding the workpieces together.
In many instances, it is desirable to position the first and second workpieces at orientations other than parallel or perpendicular to each other. To provide relative clocking (angular positioning) of the workpieces, a linear-friction-welding machine having either a stationary or a movable table could be reconfigured to allow rotation of the table relative to the weld head. However, if the movable table were configured to be rotatable, the linear-friction-welding machine would need to be substantially larger, heavier, and more complex to accommodate angular positioning of large workpieces. Alternatively, the weld head of a linear-friction-welding machine, which has either a stationary or a movable table, may be configured to be rotatable relative to the table. Still, a rotatable weld head would also be more complex and, accordingly, heavier, thereby increasing the mass that must be oscillated to perform the linear-friction-welding operation. Not only would a larger oscillating mass be likely to increase power consumption, but the linear-friction-welding machine would now require a heavier construction to maintain the stiffness needed to oscillate the larger mass.